The objective of the study is to compare the structures and functions of the cell periphery in malignant and nonmalignant cells obtained from human biopsy and surgical specimens. The cell periphery (composed of cell surface, plasma membrane, and ectoplasm) is important in cell adhesion, locomotion, growth control, communication, and nutrient uptake. Morphological data on the cell periphery of human malignant cells, benign tumor cells, and control nontumor cells will be obtained by quantitative thin-section electron microscopy and by freeze-etch electron microscopy. These data are to be correlated with the biological behavior of the cell types, particularly the propensity for abnormal growth, invasion, and metastasis.